Many flavoring agents used in beverage preparation are essential oils or oleoresins, which are generally water-insoluble. However, flavors that are used in commercial beverages must be water-soluble or dispersible. Accordingly, carbohydrate gums are commonly employed to form flavor emulsions and these flavor emulsions are used to flavor a beverage.
All emulsions separate at a predetermined rate. The rate at which an emulsion separates is dependent upon, among other things, the difference in density between the oil and water phases; viscosity of the aqueous phase; and the size of the emulsion particles. The slower the rate of separation, the more stable the emulsion.
Useful flavor emulsions must be stable per se, i.e. in the emulsion, as well as stable in the beverage in which the emulsion is used. The stability of a flavor emulsion is largely dependent on the gum used to form the emulsion.
There are many known carbohydrate gums. Such gums may be natural or modified and include seaweed extracts such as agar, algins, and carrageenans; plant seed gums such as locust bean gum and guar gum; polysaccharide gums such as xanthan gum; plant exudates such as gum arabic, gum tragacanth, and gum karaya; and, synthetic gums such as sodium carboxymethylcellulose, hydroxypropylmethylcellulose, methylcellulose, and microcrystalline cellulose.
Of these gums, gum arabic is superior to all others and is the standard by which all other gums are measured. Gum arabic functions as an effective surfactant to keep the emulsion particles small and provides viscosity to the aqueous phase of the emulsion so that the difference in density between the oil and water phases is minimized.
True gum arabic is produced by Acacia senegal, a shrub native to the arid sub-Sahelian regions of Africa and the Middle East. Commercial production of gum arabic requires that these shrubs be exposed to severe physiological stress in the form of water depletion and heat. Gum formation permits the shrubs to store a hydrophilic form of reserve carbohydrate in response to this stress.
Despite the strong drought resistance mechanism that results in the formation of gum arabic, two droughts in the past twenty years have killed many trees and decreased production. In addition, political turmoil in the regions where Acacia senegal is grown has further exacerbated the shortage.
Accordingly, it would be desirable to provide a carbohydrate gum having emulsification properties equivalent to those of gum arabic.